Question

Here is some hardcoded syntax. IPAddr is an int, this is sqlite and will be ported to mysql.

The syntax doesnt work with AND V.IPAddr <> 0. Possibly because V is a left join and may not exist (null?). How do I get it to to succeed when V == null || V.IPAddr <> Val?

select Post.id, name, body,
      (select count() from Votes where id=Post.id AND (type & 4)<> 0) as DV
   from Post 
left join Votes as V on V.id=Post.id
   where flag='1'  AND V.IPAddr <> 0 AND DV<1
   limit 1

Answer 1

Move the outer filter to the JOIN condition. Otherwise, the filter changes it to a INNER JOIN

select Post.id, name, body,
(select count() from Votes where id=Post.id AND (type & 4)<> 0) as DV
from Post 
left join Votes as V on V.id=Post.id AND V.IPAddr <> 0 
where flag='1' AND DV<1
limit 1